CODEWITHSUNDEEP
clojure
Alexander
Alexander

Reputation: 241

Convert clojure persistant vector to maps

I'm trying to learn clojure.

I am calling a function which is returning me an array of strings..

If I do: 

(let [items (get-all-items)]
    (println (type items))
    (items))

the type of items is shown as class clojure.lang.PersistentVector where as the items value is like so: 

[["Dogs"] ["Cats"] ["Capybaras"] ["Pygmy Hedgehogs"]]

I would like to convert this to a map in a format like this: 

{ "Dogs" "Cats" "Capybaras" "Pygmy Hedgehogs" }

Does that make sense? Clojure maps can contain list of strings right?

I am only doing this because if I have it as a map, I can check if I have a pet in the list like this: 

(contains? pets "Dogs")
; assuming the map is stored in pets variable

that fails if pets is a vector.

So If I can convert that to maps, how do I convert it? if not, how do I search for something in the vector?

(I like working with maps so I'd rather have maps - unless there is a strong reason not to do so)

ps: I've tried converting with into but that doesn't work either.

Upvotes: 3

Views: 1651

Answers (2)

Francis Avila
Francis Avila

Reputation: 31621

I suspect what you really want is a set, not a map. Maps store a value associated with a specific key. Sets store a unique list of values.

If your only use case is testing for membership, then you definitely want a set. You want a map if you are also associating some data with that key.

It's very easy to produce a set from any sequence. In your case:

(set (flatten items))
;;=> #{"Pygmy Hedgehogs" "Dogs" "Cats" "Capybaras"}

flatten removes the nesting on your lists giving you a sequence of strings. set consumes the sequence and returns a set of the unique values in that sequence.

Upvotes: 3

Michiel Borkent
Michiel Borkent

Reputation: 34800

(apply assoc {} (flatten [["Dogs"] ["Cats"] ["Capybaras"] ["Pygmy Hedgehogs"]]))
;;=> {"Capybaras" "Pygmy Hedgehogs", "Dogs" "Cats"}

Upvotes: 3

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